consumers.erl

-module(consumers).
-export([start/0, consumer1/0]).

start() ->
    loop([]).

loop(Consumers) ->
    receive
        {subscribe, Consumer} ->
            ConsExits = lists:member(Consumer, Consumers),
            if
                ConsExits =/= true ->
                    loop([Consumer|Consumers]);
                true -> loop(Consumers)
            end;
        {exit, Consumer} ->
            Consumer ! {exit},
            loop(lists:delete(Consumer, Consumers));
        {msg, Msg} ->
            process_msg(Msg, Consumers),
            loop(Consumers);
        consumers ->
            io:format("Consumers: ~p~n",[Consumers]),
            loop(Consumers);
        exit -> ok;
        _ -> loop(Consumers)
    end.

process_msg(_, []) -> ok;
process_msg(Msg, [H|T]) ->
    H ! {msg, Msg},
    process_msg(Msg, T).

consumer1() ->
    receive
        {exit} ->
            io:format("[~p] - Exit - bye.~n",[self()]),
            ok;
        {msg, Msg} ->
            io:format("[~p] - Message: ~p~n",[self(), Msg]),
            consumer1()
    end.